Montreal Uses Tethered Leak Detection Tool On Water Main
In February 2012, The City of Montreal conducted a leak detection survey using the Sahara® platform on a water transmission main in downtown Montreal that had known leaks.
The pipeline on Pine Avenue is an 80-year-old, 34-inch cage and cylinder Bonna-type pipe – a variation of Reinforced Concrete Cylinder Pipe (RCCP) – that had an unknown number of leaks that were unsuccessfully located using other non-intrusive techniques during previous inspections.
The Sahara leak detection inspection was extremely successful, locating nine leaks ranging from small to large size in the 1.3-kilometer (0.8 miles) survey. The City was expecting to find one major leak and possibly another minor one and was surprised at the number of leaks identified.
The Pine Avenue pipeline is a critical supply of potable water to the western portion of a major sector in the city, which made it important for the City to locate and repair the suspected leaks.
The City had been working with Pure Technologies in pipeline assessment program since 2007 that included electromagnetic (EM) inspection and acoustic monitoring, which prompted the decision to use Sahara leak detection on Pine Avenue.
The Sahara platform is a non-destructive tool equipped with acoustic leak detection and inline video that is pulled by the water flow by a small drag chute and used to locate leaks, gas pockets, and internal pipe conditions in live, pressurized pipelines. When the sensor is inserted into a tap, it remains tethered to the surface to allow for confirmation of suspected leaks. The sensor is also tracked along the surface, allowing for precise marking of leaks in real time.
Regular leak detection surveys can help utilities identify leaks that may not be visible at the surface and may have been leaking for a long time. By repairing leaks, it reduces Non-Revenue Water and can potentially prevent pipeline failures, as the presence of leaks is often a preliminary indication that a pipe will eventually fail.
In August 2012, the City excavated all nine leaks for repair. The leak locations had been precisely identified and marked on-site during the inspection and all leaks were found within 1-meter (3-feet) of the marked location. All of the leaks also had a size that corresponded with the estimates made by Sahara technology.
Highly accurate inline leak detection systems that can detect leaks and gas pockets in operational pipelines. These systems are used primarily on larger diameter water and wastewater transmission mains of all materials as well as oil & gas pipelines.